Zeroth Law

Laws of thermodynamics

Zeroth Law:
Deals with the concept of thermal equlibrium and provides means of measuring temperature.

This law by R.H.Fowler in 1931.

If two systems say A & B are separately in thermal equilibrium with the third system C. i.e.
TA=TC and TB=TC then systems A & B are to be in equilibrium i.e. TA=TB........means
If two bodies have equality in temperature with a third body, they have to be equality mutually with each other. This law is basis of temperature measuring. The only device working on this principle is thermometer. Draw the sketch.






First Law of thermodynamics: Deals with concept of energy conservation(protection) and introduces the concept of internal energy (IE )
Explain Joule's Paddle Wheel Experiment.